Medical Microbiology Department, College of Medicine, Al-Nahrain University, Baghdad, Iraq.
Basic and Medical Sciences Branch, College of Nursing, University of Al-Ameed, Karbala, Iraq.
J Med Life. 2023 Jun;16(6):883-889. doi: 10.25122/jml-2023-0047.
The RBD, S, and N proteins, the three main antigens of the SARS-CoV-2 virus, activate the host immune system and cause the formation of IgM and IgG antibodies. While IgM indicates an early, acute infection stage, IgG shows a past infection or persistent sickness. This study used an indirect ELISA assay that targets the S1 subunit of the SARS-CoV-2 S protein to create an in-house, qualitative serological test specific to COVID-19. A total of 60 serum samples were examined using ELISA for anti-SARS-CoV-2 IgG, and 50 of those results were positive. An additional 20 samples were taken from cases that occurred before the pandemic. For the in-house ELISA assay, a plasmid containing the gene coding for the S1 subunit was transformed into DH5ɑ bacterial cells and the protein was synthesized and purified. The purified protein was utilized to coat the ELISA plate, which was subsequently used to assess the levels of IgG among individuals with SARS-CoV-2 infection. The study found a significant association (p-value=0.01) between the in-house and the commercial anti-S1 subunit IgG antibodies kits. The in-house ELISA responded well, with a sensitivity and specificity of 75.0% and 88.89%, respectively. Furthermore, a library of SARS-CoV-2 recombinant S1 subunits was created by competent bacteria and may be employed for various tasks, such as creating diagnostic tools and scientific investigation. Overall, the in-house anti-SARS-CoV-2 human IgG-ELISA proved to be sensitive and specific for identifying IgG antibodies in patients exposed to SARS-CoV-2.
SARS-CoV-2 病毒的三个主要抗原 RBD、S 和 N 蛋白激活宿主免疫系统，导致 IgM 和 IgG 抗体的形成。虽然 IgM 表明处于早期、急性感染阶段，但 IgG 表明过去感染或持续患病。本研究使用针对 SARS-CoV-2 S 蛋白 S1 亚单位的间接 ELISA 检测试剂盒，开发了一种针对 COVID-19 的内部定性血清学检测方法。共使用 ELISA 检测了 60 份血清样本中的抗 SARS-CoV-2 IgG，其中 50 份结果为阳性。另外还从大流行前的病例中采集了 20 个样本。对于内部 ELISA 检测，将含有编码 S1 亚单位的基因的质粒转化到 DH5ɑ 细菌细胞中，并合成和纯化蛋白质。将纯化的蛋白质用于包被 ELISA 板，然后使用该板来评估具有 SARS-CoV-2 感染的个体中的 IgG 水平。研究发现内部 ELISA 与商业抗 S1 亚单位 IgG 抗体试剂盒之间存在显著关联（p 值=0.01）。内部 ELISA 反应良好，灵敏度和特异性分别为 75.0%和 88.89%。此外，通过感受态细菌创建了 SARS-CoV-2 重组 S1 亚单位文库，可用于创建诊断工具和科学研究等各种任务。总体而言，内部 SARS-CoV-2 人类 IgG-ELISA 被证明在识别接触过 SARS-CoV-2 的患者的 IgG 抗体方面具有敏感性和特异性。
